ul {
  margin: 0;
  padding: 0;
}

a {
  text-decoration: none;
  color: white;
}

li {
  list-style-type: none;
}

nav, .nav-submenu-list {
  background-color: #25383C;
  text-align: center; /*为了让文字居中*/
}

.nav-container-list {
  max-width: 1280px; /*最大宽度不超过1280px*/
  margin: 0 auto; /*容器居中*/
}

.nav-list-item {
  display: inline-block;
  position: relative;
}

.nav-list-item a {
  display: block; /*设置为块级元素才能使上下内边距生效*/
  padding: 20px 40px;
  width: 25%;
}

.nav-submenu-list {
  display: none;

  position: absolute;
  left: 0;
  top: 100%;
}

/*使用> 箭头 找到子元素 但不包含子元素的子元素*/
.nav-list-item:hover> ul{
  display: block;
}










